The present invention pertains to a multi-function riveting/fastening machine of the type used for attaching frames and stringers to the skin for fuselage and wing panels of large commercial aircraft. Structures of this type may range from a few feet up to forty feet or more in length, and up to ten or more feet in width.
Heretofore, panels of this size have been riveted, using stationary C-frame riveting machines and a movable workpiece holder and positioner. The C-frame riveting machine is what is known as a "hard automation" machine, that performs the functions of part clamping, drilling, counter-sinking, rivet feeding, and rivet squeezing in automatic succession. The workpiece is moved in a generally horizontal position from one rivet position to the next by the holder and positioner, which is usually computer controlled and has up to five degrees of freedom of motion. In some cases, the C-frame riveting machine may be movable along the longitudinal axis of the workpiece, with the workpiece holder and positioner being movable along other linear and rotational axes. This process is very effective and reliable as far as the process of putting rivets into structure is concerned, and is well suited to the assembly of small- to medium-sized panels. However, as panels become larger, there is a serious problem with the handling of the large structures due to the weight of the part positioner, and unpredictable deflection of the part and holder. The workpiece holder and positioner becomes very complex and costly, and must be "fine-tuned" for precision in placing the rivets. One disadvantage of this prior art arrangement is that it requires a large floor space area to allow the panel to be moved in all directions. Since the workpiece and holder must be moved from each rivet position to the next, and the workpiece and positioner are relatively flexible, with a certain amount of unpredictable deflection, it is a time-consuming operation, especially since with the huge machine with its large floor space, only one rivet can be placed at a time.